Study of Stable Combustion Ranges of Diffusion Flame Microjet of Hydrogen Effluent from around Micronozzle at Addition of Inert and Reactive Gases into Hydrogen or Air
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The effect addition of inert (He, N2, Ar, CO2) and reacting (СН4, O2, CF3Br, (CH3O)3PO) gases in a hydrogen or in coflowing air stream on lift-off diffusion flame conditions of hydrogen micro jet effluxed from the round micro nozzle was experimentally studied. Using the schlieren technique a critical hydrogen flow rate was established at which the flame of the hydrogen microjet detaches from the nozzle when introducing additives of the studied gases into both air and hydrogen. It has been established that the addition of all the studied gases to the hydrogen leads to a decrease in the velocity range of its microjet at which flame stabilization is possible, regardless of whether the gases introduced into hydrogen are inert or reactive. It is shown that in the case of the addition of various gases to the hydrogen, the main factor determining the critical flow rate at flame lift-off from the micro nozzle is the average molecular weight of the H2 gas mixture with additives. At addition of the studied gases into the coflowing air, the critical flow rate of H2 is determined by their affect on the chemical reactions of hydrogen oxidation (inhibition effectiveness), as well as by a decrease in oxygen concentration due to dilution of air by additives. The data obtained are of interest to hydrogen energy in terms of determining the limits of sustainable combustion of the hydrogen microjet, as well as determining the minimum phlegmatizing concentrations of additives of inhibitors and fire suppressant in the air, preventing the ignition and explosion of hydrogen in case of emergency at its leak.
Keywords
hydrogen microjet, flame detachment, coflow air stream, round micronozzle, fire retardant, phlegmatizer
Funding
This work was supported by the Russian Science Foundation, project number 16-19-10330
УДК 532.525.2
Study of Stable Combustion Ranges of Diffusion Flame Microjet of Hydrogen Effluent from around Micronozzle at Addition of Inert and Reactive Gases into Hydrogen or Air
The material was received by the Editorial Board: 01.02.2019
Abstract The effect addition of inert (He, N2, Ar, CO2) and reacting (СН4, O2, CF3Br, (CH3O)3PO) gases in a hydrogen or in coflowing air stream on lift-off diffusion flame conditions of hydrogen micro jet effluxed from the round micro nozzle was experimentally studied. Using the schlieren technique a critical hydrogen flow rate was established at which the flame of the hydrogen microjet detaches from the nozzle when introducing additives of the studied gases into both air and hydrogen. It has been established that the addition of all the studied gases to the hydrogen leads to a decrease in the velocity range of its microjet at which flame stabilization is possible, regardless of whether the gases introduced into hydrogen are inert or reactive. It is shown that in the case of the addition of various gases to the hydrogen, the main factor determining the critical flow rate at flame lift-off from the micro nozzle is the average molecular weight of the H2 gas mixture with additives. At addition of the studied gases into the coflowing air, the critical flow rate of H2 is determined by their affect on the chemical reactions of hydrogen oxidation (inhibition effectiveness), as well as by a decrease in oxygen concentration due to dilution of air by additives. The data obtained are of interest to hydrogen energy in terms of determining the limits of sustainable combustion of the hydrogen microjet, as well as determining the minimum phlegmatizing concentrations of additives of inhibitors and fire suppressant in the air, preventing the ignition and explosion of hydrogen in case of emergency at its leak.
Keywords
hydrogen microjet, flame detachment, coflow air stream, round micronozzle, fire retardant, phlegmatizer
Funding
This work was supported by the Russian Science Foundation, project number 16-19-10330
УДК 532.525.2
Study of Stable Combustion Ranges of Diffusion Flame Microjet of Hydrogen Effluent from around Micronozzle at Addition of Inert and Reactive Gases into Hydrogen or Air References: Shmakov A. G., Kozlov V. V., Litvinenko M. V., Litvinenko Yu. А. Study of Stable Combustion Ranges of Diffusion Flame Microjet of Hydrogen Effluent from around Micronozzle at Addition of Inert and Reactive Gases into Hydrogen or Air. Siberian Journal of Physics . 2019, vol. 14, no. 3. P. 64–75. (in Russ.). DOI: 10.25205/2541-9447-2019-14-3-64-75